The invention relates to an artificial knee joint consisting of a convex femoral part and tibial part, which performs a rolling and sliding movement at the femoral part, which comprises smaller radii of curvature as flexing increases, with the femoral part and tibial part respectively comprising a lateral guide surface and a medial guide surface.
A knee joint prosthesis having a convex femoral part and having concave guide surfaces on the tibial part is shown in U.S. Pat. No. 4,568,348. This arrangement has the disadvantage that the guidance of the tibial part on a plane perpendicular to the flex axis is restricted on the femoral part by lateral guide shoulders and concave guide surfaces on the tibial part abutting lateral guide shoulders and convex guide surface of the femoral part.